The present invention relates to apparatus for supporting, positioning and transporting hydroponic growing troughs and to a method for transferring growing plants.
For a variety of reasons, commercial scale cultivation of plants such as lettuce under controlled hydroponic conditions is on the increase. Rising transportation costs for field-grown produce, together with significant improvements in yields and quality possible in controlled environment growing systems, provide economic justification for the expense of controlling the nutrient supply and growing environment. Since the costs of heating, lighting and other aspects of environmental control is in large measure a function of the area being controlled, elaborate handling systems have been developed for progressively transporting the plants toward a harvesting station as they grow, so as to minimize the total growing space required. Typically these handling systems are designed to operate automatically or semi-automatically. Examples of such relatively complex handling apparatus for hydroponic systems are shown in U.S. Pat. No. 4,216,618 of Haub et al. and No. 4,028,847 of Davis et al.
Investment in sophisticated automated control equipment for maintaining both the environment and the liquid nutrient supply within close tolerances usually will result in lower net cost for marketable plants, because of the important effect such controls have on growth rate, yield, and quality. The same is not necessarily true for investment in complex automated apparatus for transporting the growing plants through a growing chamber or greenhouse. While the ability to move large arrays of plants easily and quickly is important, the use of complicated machinery for this purpose has a number of disadvantages. Obviously, such equipment is expensive. Plant handling and transport equipment is necessarily exposed to the warm, relatively humid growing environment, which is not favorable for electrical equipment or machinery. The growing plants typically require movement only at infrequent intervals, so that the usage factor for the transport mechanisms is low. In addition, providing complex mechanized plant transport systems can increase rather than decrease labor costs, since skilled maintenance and repair personnel are paid more than plant handlers and harvesters.